GGUI::TextEngine class

#include <GGUIText/Public/TextEngine.h>

Public types

struct Stats

What the engine has done since it was made.

class AtlasHold

While one of these exists no glyph is added, so the pages stay as they are: for whoever copies them while documents may be being updated on other threads.

struct ShapedGlyph

One glyph of a run as shaped, in the order it is drawn: for tests and tools.

Public static variables

static uint32_t PageSize constexpr

an atlas page's width and height, in pixels

Constructors, destructors, conversion operators

TextEngine()

An engine with no fonts; Initialize it before use.

~TextEngine()

TextEngine(const TextEngine&) deleted

Public functions

auto operator=(const TextEngine&) -> TextEngine& deleted

auto Initialize() -> bool

Start FreeType and HarfBuzz. False if they couldn't be; nothing loads until this is true. Calling it again does nothing.

auto LoadFont(const char* path) -> FontID

Load a font file (TrueType or OpenType). The first font loaded is font 0. NoFont if it can't be read, or the engine isn't initialized.

auto FontCount() const -> uint32_t

How many fonts are loaded.

void AddFallbackFont(FontID font)

A font to draw characters from when the font being used does not have them. Fallbacks are tried in the order they were added.

void NameFont(std::string_view name, FontID font)

The name styles ask for a font by (.Font = FontNamed("mono"), font: mono).

void SetDefaultStyle(const FontStyle& style)

The font text uses when its style class has none of its own.

void SetClassStyle(std::string_view className, const FontStyle& style)

The font a style class's text uses.

auto Measurer() -> TextMeasurer

What a document measures text with (UIContext::SetTextMeasurer). It refers to this engine, which must outlive every document using it.

auto Glyphs() const -> const GlyphSource*

What a document draws text from (UIContext::SetGlyphSource). The same lifetime.

auto PageCount() const -> uint32_t

How many atlas pages there are.

auto Page(uint32_t index) const -> AtlasPage

Atlas page index. Read it while holding the atlas (AtlasHold) if documents may be updating.

auto TakePageChanges(uint32_t index, uint32_t& x, uint32_t& y, uint32_t& width, uint32_t& height) -> bool

The rectangle of page index that has been written since this was last called, and forget it: for whoever keeps a copy of the page (a texture) to update only that.

auto ReferenceSampler() const -> ReferenceTextures

For the reference rasterizer: glyph primitives sample these pages.

auto GetStats() const -> Stats

What it has done so far.

auto Inspect(uint64_t run) const -> std::vector<ShapedGlyph>

The glyphs of run (TextMetrics::Run); empty if it isn't kept.

Function documentation